Dual fountain pen



Dec. 28, 1948. M. ERNST DUAL FOUNTAIN PEN Filed July 15, 1945 /Illll MHWI fl,

Lil M w Paiented Dec. 2.8,' 1948 orsiicizff] 15 DUAL FOUNTAIN PEN MaxErnst, Wiesendangen, Switzerland application July 13, 1945, serial No.'604,813

In Switzerland April 30, 1945 4 Claims. (Cl. 1Z0-42.10) y 1v Inpractically all circles, especially with writers, engineers,businessmen,"teachers and pupils `alike there exists a great need for afountain pen adapted to carry two kinds of one of which may be red.

Attempts have already been made to manufacture suchvmulti-.colourfountain pens On the principle of the .multiple propellingpencils, but all these attempts, known to the applicant, have beencharacterized by too .great a mechanical complexity.

The Vobject of the present invention is a `dual fountain pendistinguishedby cheapness 'andreliability. This vfountain pen vpossessesat each .end

reservoir terminating outwardly in a nibsection `and which, inwardly, isclosed by a plunger coacting with a mechanism by means of which eachplunger can be axially displaced within the related ink reservoir.

In the accompanying drawing there is shown for purposes of illustrationone preferred embodiment of the invention.

Fig. 1 is a lateral view of the dualfountain D911,

Fig. 2 shows a fragmentary cross-sectional view taken on an enlargedscale from Fig. 3,

Fig. 3 represents a longitudinal section of the fountain pen taken on anenlarged scale on the line III-III of Fig. 1.

With reference to said annexed drawing, numeral I designates a tubularcenter piece or operating member provided outside with a knurling I a.Each end of the centerpiece is fitted with a screw-thread of low pitchIb, Ic, respectively. Each of these threads enters an. ink reservoir 2,3, respectively, terminating in a nib-section 4 or 5. 6 and 'I denotethe two pertinent usual ink feeders threaded into the ends of the inkreservoirs 2, 3, numerals 8 and 9 designating the two protective capsscrewed onto the ends of the ink reservoirs 2, 3.

On the inside the two ink reservoirs 2, 3 are each closed by an axiallyslid-able plunger Il), I`I, respectively, seated on spindles I2, I3,spindle I2 being hollow and provided inside With a screw-thread I2a ofhigh pitch, while the solid spindle I3 carries an external thread I3alikewise of high pitch.

As apparent especially from Fig. 2, the centerpiece I is integral withthe cylinder I4 arranged therein. Internally andv externally thiscylinder is provided with screw-threads Illa, I4b, respectively, of highpitch, which threads correspond with those I'2a and I3a of the spindlesI2 and I3 fitted to the hollow cylinder I4.

intellectual professional Theinanipulation `and operation of Ithe aore.-described'dualv fountain pen is as follows'. `lrli Figs."2and 3 'the two'plungers FI), l fare inthe inner position. Suppose now Athereservoir -3is empty and has to be lled with ink, then the-.cap 9 is `iirstunscrewed and the pen i5 dipped fas usual into `an inkwell. The lowerpart 'of the reservoir 3 is now held rmly by the one hand, :and by theother hand the vcenterpiece I-seen 'fromfthe 'nib E--is turnedclockwise. Thereby the hollow cylinder I4` is turned'together with 'theupper :reservoir 2 round about `the spindle I3, and since Vthe latter isprevented irom being carried "therewith due to friction between plungerI-I andinner wall of reservoir l3, the vspindle I3 togetherv withplunger I'l becomes axially displaced in the ldirection of the arrow Aindicatedin Fig. 2 until the plunger II eventually abuts on the lowerend 3a of reservoir 3. By turning the centerpiece I it is simultaneouslyscrewed out of the reservoir 3 the axial distance L. The thread I cbeing, however, longer than the length of the threaded portion aroundwhich the centerpiece is screwed out of the reservoir 3, the connectionbetween these two parts is maintained in any position.

As soon as the plunger Il abuts on the lower end 3a of reservoir 3, thecenterpiece I is turned in the opposite direction, whereby spindle I3and plunger I'I are raised, that is, moved in a direction opposite tothat indicated by the arrow A and ink is drawn into the reservoir 3. Theprocess is similar when the other reservoir 2 is to be lled; namely, thestructure 2 is prevented from rotating while the actuating means I ismoved clockwise or unscrewed in order to axially extend the plunger I0and its operating rod I2, such rotation of I being in the same directionas that previously employed above to withdraw the opposite plunger IIwhen the pen was inverted. When the plunger I0 has travelled outward thelength of the reservoir 2, it is retracted by reverse rotation of thecenterpiece I, thus causing ink to be sucked into the reservoir. It isthus seen that, whichever reservoir 2 or 3 is being filled or emptied,the centerpiece I is unscrewed or screwed into one reservoir the axialdistance L while the corresponding plunger moves in the oppositedirection the much greater length of the reservoir, these axialmovements being proportionate to the different pitches of threads Ic andI3a or of Ib and Illa as the case may be.

When the plunger I0 or Il returns to the position shown in Figs. 2 and3, the centerpiece I too is at the same time again firmly threaded intothe reservoir 2 or 3. Since the hollow cylinder I 4 adapted to thecenterpiece is not hollow throughout, but closed at one end, plungerpackings I5 and IB prevent ink from flowing from one reservoir into theother. In order to prevent leakage, even in regions of rarefled air,say, in the mountains, especially with the barrel held downwards, theprotective caps 8, 9 t snugly with a shoulder 8a and 9a, to outer frontrims 2bgand'3b so as to render the barrel fluid tight. i

Alternatively, the object of the invention may likewise be utilized aswriting instrument with two different nibs, one soft and one hard. iThus, for instance, a standard writing pen may be set in at the one end,while the other end of .the

holder carries a special signature pen.

Instead of providing the centerpiece with ends threadedly engaging thereservoir 2 and 3, it might also be possible to have each of thereservoirs rotatably arrangedon a stud of the centerpiece. T o securethe position in `axial direction these studs could be .designed with anannular groove ,snugly engaged bythe related reservoir. fr, WhatI claimis: v u In a dualfountain pen having van ink reserypindisposed at eachend thereof, and a plunger operatively mounted in each reservoir, theimproyement comprising: an inwardly extending, threaded spindleconnected to each plunger; and an operating ymember rotatable withrespect to said dual fountain pen and threadedly connected to eachspindle, whereby rotation of said member servesselectivelyto effectaxial reciprocal move nient of either plunger.

2.Theimprovement of the preceding claim wherein,one'of said spindles isinternally threaded and the other is externally threaded at theirrespective portions which are in threaded registration with saidoperating member.

3. The improvement of the preceding claim wherein said operating membercomprises a hollow cylinder threaded both internally and externally anddisposed with its inner and outer faces in threaded registration withthe respective spindles.

4. The improvement of claim 1 wherein said operating member is connectedto said dual fountain pen by threads of lesser pitch than those of eachspindle whereby upon manipulation, said member moves axially opposite toand a lesser .distance than the axial movement of the particu- MAXERNST.

REFERENCES CITED The following references are of record in the rilev ofthis patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date Great Britain 1929Great Britain 1939 France 1923 Germany 1937 Number Number

